Role for SCIT

October 6, 2020
Role for SCIT

Question
Because of the huge safety profile of SLIT versus SCIT, in terms of both recorded deaths and episodes of anaphylaxis, is there any role at all for SCIT in treating aeroallergen disease in countries where both are available and approved?

Answers
Yes, there is a role for SCIT (subcutaneous immunotherapy) in countries where both SCIT and SLIT (sublingual immunotherapy) are available and approved.

AIT (allergen immunotherapy) is considered the unique treatment with the potential to modify the natural history of allergic disease. The most widely used AIT modalities are SCIT and SLIT; both have similar efficacy in patients with IgE-mediated respiratory diseases such as allergic rhinitis (1). The foremost disadvantage of SCIT is the higher frequency of hypersensitivity reactions including systemic, even fatal, ones. This significant inconvenience has led to several recommendations and procedures to minimize the life-threatening risk of SCIT (2,3), such as:

• Thorough evaluation of patient’s risk factors for severe reactions prior to the allergy shot (e.g., use of raw allergen extracts, uncontrolled asthma, use of some medications, underlying mastocytosis, previous episode of anaphylaxis).
• Close monitoring of the patient for 30 minutes after the injection by healthcare personnel trained in the early recognition and immediate management of anaphylaxis.
• Immediate access to resuscitation equipment.
• Use of modified or recombinant hypoallergenic allergen derivatives.

On the other hand, a key advantage of SCIT over SLIT is adherence to therapy. Incorvaia et al (4) reported that only 13% of patients receiving SLIT completed the recommended three years of treatment, while Lemberg et al (5) described less abandonment in the group of patients receiving SCIT (5). Major reasons for poor adherence to SLIT include higher cost and more frequent dosing compared to SCIT (daily versus weekly/monthly, respectively), especially in countries where AIT is not funded by insurance (6).

In conclusion, the prescription of AIT route (SLIT or SCIT) when both are available should be personalized considering efficacy, safety and cost of the specific allergen derivative, and patient’s preferences after a detailed discussion with the providing physician.

References

1. Mustafa SS, Bingemann T, Blue H, Conn K, Hanley T, Ramsey A. Systemic reactions to subcutaneous immunotherapy: Effects of dosing and aeroallergen content. Ann Allergy Asthma Immunol. 2019;123(3):284-287. doi:10.1016/j.anai.2019.06.021.
2. Muraro A., Graham R., EAACI Guidelines on Allergen Immunotherapy: Allergic rhinoconjunctivitis. Allergy. 2017. Volume 73, Issue 4.
3. Calderón MA, Vidal C, Rodríguez Del Río P, et al. European Survey on Adverse Systemic Reactions in Allergen Immunotherapy (EASSI): a real-life clinical assessment. Allergy. 2017;72(3):462-472.
4. Incorvaia C, Mauro M, Leo G, Ridolo E. Adherence to Sublingual Immunotherapy. Curr Allergy Asthma Rep. 2016;16(2):12. doi:10.1007/s11882-015-0586-1.
5. Lemberg ML, Joisten MJ, Mosges R. Adherence in specific immunotherapy. Hautarzt. 2017 Apr;68(4):282-286.
6. Tat TS. Adherence to Subcutaneous Allergen Immunotherapy in Southeast Turkey: A Real-Life Study. Med Sci Monit. 2018;24:8977-8983. Published 2018 Dec 11.

María Teresa Gonzáles-Enriquez, MD
Allergy and Clinical Immunology
National Health Institute
Lima, Perú

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